The invention relates to devices for attaching hoses, pipes or other tubular bodies to other tubular bodies or to housings, casings or like parts. More particularly, the invention relates to improvements in fittings which can be used to engage the internally and/or externally ribbed and/or grooved end portions of tubular bodies. Still more particularly, the invention relates to improvements in fittings of the type wherein a tubular section of a sleeve serves to surround the end portion of an externally grooved hose, pipe or other tubular body and the sleeve has at least one protuberance which is receivable in an external groove to thus oppose undesirable extraction of the end portion of the tubular body from, or any other axial shifting of the end portion relative to, the tubular section.
Published German patent application No. 36 26 403 of Lanz discloses a fitting wherein the tube-receiving end of a sleeve is provided with four axially extending prongs having radially inwardly extending free end portions which can snap into the external groove of the end portion of a tubular body to hold the end portion in the interior of the sleeve. A drawback of the fitting of Lanz is that proper retention of the end portion of an externally grooved tubular body is possible only if the sleeve is provided with a substantial number of prongs. Furthermore, it is rather difficult and time-consuming to disengage the numerous prongs from the inserted end portion of a tubular body. Still further, adequate elasticity of the prongs is ensured only by employing relatively long prongs which can be achieved only by increasing the axial length of the sleeve. This, in turn, reduces the versatility of the fitting.
European Pat. No. 0 046 616 to Nicholas discloses a fitting which serves to simultaneously receive the end portions of two externally grooved and ribbed tubular bodies. The sleeve of the fitting has two pairs of axially extending prongs with radially inwardly extending ribs. The ribs of one pair of prongs are receivable in an external groove of the end portion of a first tubular body which has been introduced by way of one axial end of the sleeve, and the ribs of the other pair of prongs are receivable in an external groove of the end portion of a second tubular body which is to be introduced through the other end of the sleeve. Circumferentially spaced apart internal stops are provided in the sleeve to limit the extent of penetration of the tubular bodies. The sleeve is relatively long and the extraction of ribs from the external grooves of the respective tubular bodies necessitates the utilization of tools. Extraction of the tubular bodies is difficult on the additional ground that the relatively short axially extending prongs offer a pronounced resistance to outward flexing if they are to reliably hold the inserted end portions of tubular bodies. The versatility of the patented fitting is unsatisfactory because it can be used only as a means for coupling two externally corrugated hoses or analogous tubular bodies end-to-end.
Other conventional fittings are disclosed in published German patent application No. 29 06 317 of Offringa, in British Pat No. 1,600,912 to Wavin B. V. and in published German patent application No. 37 21 354 of Lanz. Reference may also be had to U.S. Pat. No. 4,368,904 to Lanz which discloses a composite multiple-component connection fitting for reception and retention of the end portions of flexible corrugated tubing.